She's Scotland's best-selling female artist of all time, but Barbara Dickson has a curiously low profile in the country of her birth. Perhaps we need to reacquaint ourselves with a woman we don't know so well, after all.

So, what can I do for you?" The person asking is Barbara Dickson, and given that it's 10am and she was onstage at Newcastle's Sage concert hall last night, she's looking remarkably fresh-faced. No make-up, bold angular specs, dressed all in black, Dickson doesn't look any different to the last time I caught sight of her, on one of her recent album covers, and is still easily recognisable as the shaggy-permed pop star who had a string of hits in the 1970s and 1980s, although, happily, the curly hair is gone.

Embarrassingly, I don't really have an answer to her question, or at least not a neat one. I'm there because Dickson is about to come to Scotland on tour. I'm there because in our house when I was growing up there were at least two Barbara Dickson albums that my dad would play of a Friday night, lamenting that she'd forgotten her folk roots. I'm there because I want to know why a woman who has been performing for more than 40 years still wants to go on the road each year doing 30 dates, but who has such a low profile in Scotland that everyone I mentioned her to sang a song from 20 years ago and then … well, nothing.

Dickson has recorded more than 20 albums. She is, she tells me, the biggest-selling Scottish female recording artist of all time. She's also a respected actor and has starred in stage shows on the West End. It'd be rude to ask where she's been, but only reasonable to wonder why she's so ignored in Scotland? This is the year of Homecoming, after all. No offence Sandi Thom, but surely Dickson should've been there?

"Homecoming?" she asks bluntly, "I've never been asked to come home. I wasn't invited to participate in anything to do with launching that. I never even got an invitation to the opening of the Parliament." Why? What's she done to be so left out? She's lived in Lincolnshire for a long time with her husband, TV producer Oliver Cookson, where she brought up three sons (Colm, 23, Gabriel, 20 and Archie, 18), but Sean Connery lives on a golf course in the Bahamas and he's always the guest of honour. And it's not that she's without fans. The Carnegie Hall in her hometown of Dunfermline is sold out and she's playing in major venues in Glasgow, Edinburgh and Aberdeen. "Maybe people just don't think about me, maybe they've forgotten," she says, not sounding the least bit sorry for herself. "It doesn't offend me but it

does hurt me that they ask other people who don't live in Scotland who have nothing like the commitment to or the depth of feeling about Scotland that I have.

"I think there are people all over Scotland, and elsewhere, who think of a woman with great big curly hair singing I Know Him So Well. That's the photograph they have in their heads, but people do not know me so well. They do not."

She could be right. It could also be that she's a victim of her own talent, too difficult to pigeonhole: a fine folk singer, a talented actor and, more to the point, a clear-sighted, opinionated woman who knows, and has always known, what she wanted. Being a pop star? "A Faustian pact". Parties in LA? "Never what I wanted. It's crap." Sell-out shows in the West End? "Hated it." I admire her outspokenness, but can't help but wonder if it's what has led her away from the very thing she wants. I'm surprised by how passionate she is, how frustrated she is by the misconceptions that exist of her as "a woman in a long frock, singing with an orchestra". There's none of that, she tells me. And she's never done that, but people think she has because of the connection to musical theatre. Is that why she tours – to put that right?

"I want to blow wide open misconceptions about me as a kind of glamorous musical theatre person, this ex-pop star, this lightweight. That's what I'm doing. It's a sort of mission to stick two fingers up to the people who dismiss me."

She looks out the window beside us that frames a slab of the concrete grey Tyne. "That building over there is the Guildhall – the one with the white clocktower on the top. I played there in 1972. I could fill that hall then. I would arrive from Edinburgh or wherever I'd been, someone would pick me up, I'd stay with someone else and then over a week I'd play in the folk clubs around the area. The exercise of playing live is utterly hard-wired into me. It's an unbroken line that goes back to me aged 17 singing in Dunfermline, or doing the floor spot in Kirkcaldy or in the folk club in St Andrews. The audiences have got bigger, but there are still some of those people there.

"At one point someone had the temerity to say, 'do you think that people are interested in someone like you doing concerts? Do you think there's an audience that wants to see someone who's almost 60 playing?' "

She lets the long pause signal her outrage. But there's a trace of vulnerability too.

"There was a time when I thought they were right, but fortunately I was governed by my gut and I knew that playing live is what I do, it's what I am. It's what I've always done and I'm very good at it. It might sound pompous and I don't care if it does, it's what I am. It's my vocation to do this. I don't do it for attention and I don't do it for the money, I do it because I want to."

I feel like I'm being told off as Dickson runs through her diatribe in her clipped, Fife accent. It's as though she's saying the things that she meant to say to all those people who doubted her, who have tried to push her in a direction she didn't want to go. Although sitting with her, I can't imagine who'd be brave enough. Surely she must have been viewed as – how can I put this delicately – difficult?

"Oh yeah, I was a nightmare. A complete nightmare," she says without a pause and with a smile. "I would never play the game. I always wanted it on my own terms."

In 1977, with two hit singles behind her, her manager wanted to base her in Los Angeles, where he thought she would be a huge success. She said no because she didn't want to "lose her soul".

"There was always the chance that I might have liked it. I might've got immersed in it and then I would've hated myself."

I'm definitely warming to the gruff demeanour but I don't get it – she might have liked it and that would have been a bad thing?

"I'm not sure I understand that myself," she says. "I think it's a weird psychology – I was afraid that I might get lost in the machine and I'd never be able to get out."

And with that bit of garbled logic, maybe she has got it. Dickson doesn't and never did want to be famous. In our era of celebrity, reality obsession, that's a tricky concept to grasp, but that's it. Maybe it's cost her a few opportunities, a few invites to flash parties, but then again, she's done a bit of that and she didn't like it. What's harder to reconcile is the burning indignation about her lack of recognition. It's a bind. But not one that Dickson entertains. Surely she feels like she's missed opportunities?

"Never. No, because I didn't want to do it. I don't mind people coming up to me and asking if I'm Barbara Dickson but I've never wanted people to shout at me across the street. It frightens the life out of me. If people come up to me in the street and shout at me like I'm a goldfish in a bowl I hate it. I think it's abuse, I can't bear it."

Maybe her childhood explains the contradiction. Dickson grew up on a council estate in Dunfermline. The daughter of a dad who "was very Scottish – he would never say boo to a goose" and a "lairy Scouse mother" who loved art and music and made sure that her daughter and son did the same.

"It was really weird for my brother and me having my dad saying 'shh' and my mum saying 'go on, show them'. Having said that, my mother (who's still alive] wasn't very confident. She could never have pushed me, but what she did for me and my brother was to make sure we understood the validity of artistic activity. She loved paintings and she loved music, classical music particularly. It was really curious. She was from a working-class, poverty-stricken Liverpool background. Her father was quite cultured but he died when she was 12. I think she associated culture with refinement and that being in some way aspirational. She would want to project herself in that way. And she did."

In a way Dickson has done exactly the same. The other explanation for her stepping out of the limelight to some extent is that she had three children. Her sons are all involved in performing in some way and talking about them softens her. Colm, the eldest, is a sound designer trained to work in theatre but more interested in going on the road with bands. "He's very rock'n'roll," she says. "He's got ear tunnels and tattoos. It's terrible. I'm his mother, I don't want him tattooed, I want him the perfect child that he was. But he's 23 so he's too big to have his bum smacked."

Dickson thinks her middle son, Gabriel, might become an actor (he's "intense") and the youngest, Archie, wants to make a career as a musician. "He's so good. He doesn't want to be famous, he wants to play music. It's exactly like me. He wants to be a proper musician."

Speaking about her family and the parties they throw at home, when everyone does a turn, mellows Dickson (her party pieces are Glasgow street songs – Jean McPherson was a Person, or I Am a Railway Porter and my Name is Willie Wee; happily, she treats me to a rendition of this and it's very, very funny).

"I must make it clear I have nothing to complain about," she says. "If I was hit by a bus tomorrow, I've achieved an enormous amount. But it's not enough for me. People ask what is the highlight of your career and I always say I don't know, it hasn't happened yet. It's not I Know Him So Well, it's not being given an OBE (in 2002] and it's not having been – which I am – the biggest-selling Scottish female artist of all time. It's pretty neat, but it's not enough. I just want to be able to play and sing and possibly I'd like just a bit more respect for the time that I've been around. But I'm not demanding it, I'm not in a position to demand it."

Then she gathers herself and she's feisty again. "There will be people who'll say, she's got a nerve saying that, but I don't give a s**t about that. I think I've been around long enough doing what I do to demand a degree of respect."